Power conversion device

Abstract

This power conversion device is connected and fixed to a motor case that accommodates a motor, and is provided with: a case that has a plurality of side walls and has an opening on the motor side; a cover covering a top surface of the housing; and a plurality of internal components housed in the housing, the plurality of internal components including a capacitor, the housing having a connection portion connected to the motor housing and a plurality of fixing portions for fixing the capacitor inside the housing, a first space portion being provided between the capacitor and the cover inside the housing, and a second space portion being provided between the capacitor and the cover. A second space portion is provided between the capacitor and the motor, and the plurality of internal members are disposed so as to connect a pair of opposing side walls among the plurality of side walls.

Description

Technical Field

[0001] The present invention relates to a power conversion device. Background Art

[0002] Regarding the housing shape of a power conversion device for an electric vehicle or a hybrid vehicle, for example, Patent Document 1 discloses a power conversion device having a structure having a bottom surface for holding components and ensuring strength. Prior art literature Patent Literature

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 2013-115903 Summary of the Invention Problems to be solved by the invention

[0004] In Patent Document 1, the need for a larger projected area for the bottom surface increases the size of the casting machine, contributing to increased costs. Furthermore, the presence of the bottom surface in the housing divides the interior or bottom space of the housing, restricting component placement and increasing the height of the inverter. Furthermore, regarding the strength of the components, previously, individual assembly was performed, making it difficult to ensure mechanical strength. Technical means to solve the problem

[0005] A power conversion device is connected and fixed to a motor housing that accommodates a motor, the power conversion device comprising: a housing having multiple side walls and an opening on the motor side; a cover covering the top surface of the housing; and multiple internal components housed in the housing, the multiple internal components including a capacitor, the housing having a connecting portion connected to the motor housing and multiple fixing portions for fixing the capacitor inside the housing, a first space portion being provided in the housing between the capacitor and the cover, and a second space portion being provided between the capacitor and the motor, the multiple internal components being arranged in a manner that connects a pair of opposite side walls among the multiple side walls. Effects of the Invention

[0006] According to the present invention, it is possible to provide a power conversion device that achieves cost reduction, miniaturization, suppression of strength reduction, and improved assemblability. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 This is an overall perspective view of the power conversion device. Figure 2 This is an embodiment of the present invention Figure 1 Exploded diagram of . Figure 3 This is an embodiment of the present invention when viewed from the direction of arrow A. Figure 2 Cross-sectional view of the device. Figure 4 This is a plan view of an inverter case according to one embodiment of the present invention. Figure 5 1 and 2 are a plan view of a capacitor viewed from above and a front view viewed from the direction of arrow B according to one embodiment of the present invention. DETAILED DESCRIPTION

[0008] The following describes embodiments of the present invention with reference to the accompanying drawings. The following description and drawings are examples for illustrating the present invention, and appropriate omissions and simplifications have been made for clarity of description. The present invention may also be implemented in various other forms. Unless otherwise specified, each component may be single or multiple.

[0009] To facilitate understanding of the invention, the positions, sizes, shapes, and ranges of the components shown in the drawings may not necessarily represent their actual positions, sizes, shapes, and ranges. Therefore, the present invention is not necessarily limited to the positions, sizes, shapes, and ranges disclosed in the drawings.

[0010] (First embodiment and overall structure of the present invention) ( Figure 1 ) The bottom side of the inverter 1 is attached to and fixed to the motor case 2 by fastening means such as screws. The motor case 2 houses a motor (not shown) and serves as a base for the inverter 1 by attaching and fixing the inverter 1 thereto.

[0011] ( Figure 2 ) The inverter 1 includes a top cover 11 and an inverter housing 17. The inverter housing 17 is made of metal and has a plurality of side walls and an opening 1c on the motor side (motor housing 2 side) (not shown). The inverter housing 17 houses a plurality of inverter components such as capacitors 16. The top cover 11 covers the top surface ( Figure 2 The inverter housing 17 is mounted so as to protect the internal components of the inverter housing 17. The inverter housing 17 houses the LV connector 12, ground substrate 13, power module 14, bus bar 15, and capacitor 16 as internal components. Furthermore, the inverter housing 17 has a DC connector 18 on the outside of its side wall, serving as a connection interface with external components.

[0012] The LV connector 12 is a connection interface for connecting the inverter 1 to external components on the top cover 11 side and passes through the top cover 11. The position where the LV connector 12 passes through the top cover 11 is arbitrary and may pass through the top cover 11 at other positions.

[0013] The ground substrate 13 controls the inverter 1. The power module 14 converts the power input to the inverter 1 and monitors the current. It is integrated with the cooling water path (not shown) flowing within the inverter 1. The bus bar 15 connects the power module 14 to the motor (not shown) mounted in the motor housing 2. The capacitor 16 rectifies the power input from outside the inverter 1 via the DC connector 18 and flows it to the power module 14. The capacitor 16 also reduces radiation noise. The DC connector 18 is a connection interface that connects the power supply outside the inverter 1 to the inverter 1.

[0014] ( Figure 3 ) The inverter housing 17 has a plurality of fixing portions 17b for fixing the capacitor 16 inside the inverter housing 17. The capacitor 16 has fixing portions corresponding to the plurality of fixing portions 17b, and the fixing portions are aligned with each other, and are connected and fixed to the power module 14 and the inverter housing 17 by inserting fixing members 20 such as screws. In addition, the inverter housing 17 has a housing fixing portion 17a on the outside, and is connected to the motor housing 2 by inserting fixing members such as the housing fixing portion 17a to form a connecting portion 3. In the internal space of the inverter housing 17, an opening portion 1c is formed between the space where the capacitor 16 is located and the internal space of the motor housing 2. Regarding the opening portion 1c, Figure 4 To be discussed later.

[0015] The inverter housing 17 has a first space 1a and a second space 1b. The first space 1a is between the capacitor 16 and the top cover 11. The second space 1b is between the capacitor 16 and the motor housing 2 (or the motor not shown). By forming the first space 1a and the second space 1b in the inverter housing 17, not only the wiring connected to the capacitor 16 becomes easy, but also the connection between the internal components in the inverter housing 17 and the motor not shown in the figure housed in the motor housing 2 becomes easy. In addition, in Figure 4 As will be described later, the capacitor 16 functions as a beam of the inverter case 17 and contributes to ensuring the strength of the inverter case 17 .

[0016] ( Figure 4 ) The inverter case 17 has an opening 1c. The inverter case 17 also has a plurality of fixing portions 17a and a plurality of fixing portions 17b. The capacitor 16 is fixed in the inverter case 17 by the capacitor fixing portion 17b.

[0017] Conventionally, the inverter case 17 had a bottom surface, so components mounted inside the inverter case 17 could only be mounted from one direction. Furthermore, the busbars routed inside the inverter case 17 required drilling holes in the bottom surface to connect to the motor, which increased the number of manufacturing steps.

[0018] However, as in the present invention, by having an opening 1c on the bottom surface of the inverter case 17, internal components can be mounted from either side of the inverter case 17. This increases the degree of freedom in the assembly order of the internal components and makes it easier to effectively utilize the space within the inverter case 17 for component placement, thereby increasing the degree of freedom in the placement of internal components. Furthermore, the presence of the opening 1c increases the degree of freedom in the placement of busbars arranged within the inverter case 17, thereby improving space efficiency.

[0019] In addition, by providing the opening 1c in the inverter housing 17, the projected area can be reduced, thereby achieving a reduction in casting costs and weight reduction. In addition, by arranging the capacitor 16 in coordination with the formation position of the opening 1c, the capacitor 16 functions as a structural member of the inverter housing 17. Specifically, by being arranged so as to connect a pair of opposing side walls of the inverter housing 17, the capacitor 16 functions as a beam of the inverter housing 17. In addition, not only the capacitor 16 but also the power module 14 described above, by being arranged at a position within the inverter housing 17 different from the position where the capacitor 16 is arranged, functions as a beam as a structural member of the inverter housing 17. Thus, the strength of the inverter housing 17 can be ensured by the various internal components.

[0020] By being mounted on the inverter housing 17, the power module 14 and capacitor 16 function as beams within the inverter housing 17. The natural frequency varies depending on the component. Therefore, when resonance occurs, even if one component resonates, the other still functions as a beam. This dampens vibrations in the sidewalls of the inverter housing 17, suppresses deformation of the inverter housing 17, and ensures strength during resonance.

[0021] The multiple fixing portions 17b of the inverter housing 17 are needed to secure heavy components such as the capacitor 16 and power module 14 within the inverter housing 17. Therefore, the strength of the fixing portions 17b themselves needs to be increased. By making the fixing portions 17b stronger than the sidewalls, the rigidity of the sidewalls of the inverter housing 17 is lower than that of the fixing portions 17b. This allows forces applied to the walls of the inverter housing 17 to be transferred to the internal components via the fixing portions 17b. Furthermore, by increasing the rigidity of the fixing portions 17b, vibrations and shocks are prevented from being transmitted to the capacitor 16, ensuring the strength of the wall itself and improving seismic resistance.

[0022] Furthermore, as a method of increasing the rigidity of the fixing portion 17b, for example, the fixing portion 17b may be formed thick-walled or a rib may be formed on the outer circumference (outside the side wall) of the fixing portion 17b to ensure high mechanical strength.

[0023] Furthermore, the configuration of the fixing portion 17b helps address the reduced strength of the inverter case 17 caused by the opening 1c. Specifically, the wall surface of the inverter case 17, which is weaker than the fixing portion 17b, can be made thinner. Furthermore, the opening 1c allows the inverter case 17 to elastically deform, absorbing vibrations and shocks transmitted from the motor, for example, while also mitigating shocks generated by the fixing portion 17b.

[0024] Furthermore, the presence of the opening 1c eliminates the need to consider machining accuracy related to tolerances of the holes in the inverter case 17 when routing busbars and wiring connected to the motor. This can be accommodated solely by the positional tolerances of the busbars, reducing the design burden. Specifically, by eliminating the bottom surface of the inverter case 17, connectivity between components within the inverter case 17 and components located on the motor side is improved, facilitating efficient use of the space within the inverter case 17.

[0025] ( Figure 5 ) Figure 5 (a) is a top view of the capacitor 16 as viewed from the upper surface thereof, and is an explanatory diagram of the plurality of fixing portions 20a to 20e provided on the capacitor 16. Figure 5 (b) is from Figure 5 (a) is a front view of the capacitor 16 viewed from the B direction.

[0026] Capacitor 16 has fixing portions 20a to 20e for fixing to inverter case 17. The connection between capacitor 16 and inverter case 17 does not necessarily require the use of screws or the like. For example, bolts or the like may be placed on the inverter case 17 side and fixed with nuts, or a snap-fit ​​structure may be provided on the inverter case 17 or capacitor 16 for fastening by insertion.

[0027] Measures to prevent the inverter housing 17 from lateral shaking will be described. Figure 5 (a) Figure 5 The fixing portions 20a to 20e shown in (b) are provided so that the distance between the fixing portions close to each other is shortened as much as possible.

[0028] In capacitor 16, fixing portions 20a and fixing portions 20b are fixed to each other. By fastening fixing portions 20a together, a truss shape is formed by the pair of fixing portions 20a and the corner portions 16b of capacitor 16. This ensures the strength of capacitor 16 and inverter case 17, and suppresses overall vibration. Similarly, by fastening fixing portions 20b together, a truss shape is formed by the pair of fixing portions 20b and the corner portions 16a of capacitor 16. This ensures the strength of capacitor 16 and inverter case 17, and suppresses overall vibration.

[0029] In addition, by further Figure 5 By tightening the fixing portion 20c shown in (a), a small truss shape is formed by the fixing portion 20c, the fixing portion 20d formed in the width direction of the capacitor 16 near the fixing portion 20c, and the corner portion 16a, thereby suppressing vibration of the corner portion 16a of the capacitor 6. Similarly, by tightening the fixing portion 20d, a small truss shape is formed by the fixing portion 20d, the fixing portion 20a formed in the width direction of the capacitor 16 near the fixing portion 20d, and the corner portion 16b, thereby suppressing vibration of the corner portion 16b of the capacitor 6. This ensures the strength of the capacitor 16 in the inverter case 17, and further expands the range of influence of the internal components of the inverter case 17 acting as beams, thereby ensuring strength.

[0030] Furthermore, when securing the capacitor 16 to the inverter case 17 using as few fixing members as possible, prioritizing the fastening of the fixing portions 20a and 20b over the fastening of the fixing portions 20c and 20d allows for reliable strength.

[0031] Next, use Figure 5 The plurality of fixing portions 20a to 20e shown in (b) will be described as a countermeasure for the longitudinal shaking of the inverter housing 17. The plurality of fixing portions 20a to 20e include a combination of fixing portions provided at mutually different positions in the thickness direction of the capacitor 16. Specifically, Figure 5 The fixed groups of the fixing parts 20b shown in (b) are fixed to each other (the other side is Figure 5 As shown in (a), there are three groups: a group of fixing portion 20c and fixing portion 20d, and a group of fixing portion 20a and fixing portion 20e. This allows capacitor 16 to be fixed evenly to inverter case 17 with strength.

[0032] In addition, Figure 5In (b), the fixing portion 20a, the fixing portion 20b and the corner portion 16c form a truss shape, which can connect the two most separated points of the two ends of the capacitor 16, so that it can have the function of a beam of the capacitor 6 in the inverter housing 17, improve the vibration resistance, and expand the range of influence of the beam.

[0033] In addition, Figure 5 In (b), the fixing portion 20a and the fixing portion 20c as well as the fixing portion 20d, the fixing portion 20e and the fixing portion 20b can reinforce the fixation of the central portion of the capacitor 6, thereby further ensuring the strength of the capacitor 16.

[0034] In addition, as a countermeasure for the natural vibration (resonance countermeasure) of the inverter case 17, it is considered that the parts that are prone to vibration are different in each vibration mode, such as Figure 5 As shown in (b), the plurality of fixing portions 20a to 20e include a combination of fixing portions 20a to 20e arranged at the same position in the thickness direction of the capacitor 16. Specifically, in the thickness direction of the capacitor 16, the fixing portions 20b are aligned at the same position, the fixing portions 20c and 20d are aligned at the same height, and the fixing portions 20a and 20e are aligned at the same height. This improves assembly efficiency.

[0035] In this way, the above-mentioned structure of the multiple fixing portions 20a to 20e of the capacitor 16 can eliminate the potential problem of insufficient strength caused by the opening portion 1c of the inverter housing 17. Furthermore, by fastening the inverter housing 17 to the motor housing 2, the same strength as the bottom surface can be ensured, thereby ensuring strength and sealing.

[0036] Furthermore, even if vibration or shock is directly transmitted to the fixing portion when the inverter 1 is fixed too firmly, the inverter case 17 is elastically deformed by the configuration of the present invention, thereby being expected to mitigate the shock.

[0037] According to the embodiment of the present invention described above, the following effects are achieved.

[0038] (1) A power conversion device is connected and fixed to a motor housing 2 that houses a motor. The power conversion device includes: a housing 17 having multiple side walls and an opening on the motor side; a cover 11 that covers the top surface of the housing 17; and multiple internal components housed within the housing 17. The multiple internal components include a capacitor 16. The housing 17 includes a connection portion 3 connected to the motor housing 2 and multiple fixing portions 17b that fix the capacitor 16 within the housing 17. Within the housing 17, a first space 1a is provided between the capacitor 16 and the cover 11, and a second space 1b is provided between the capacitor 16 and the motor. The multiple internal components are arranged so as to connect a pair of opposing side walls among the multiple side walls. As a result, it is possible to reduce the need for reinforcing members such as a base plate, mitigate the impact on the fixing portions 20a to 20e and the capacitor 16, improve wiring layout efficiency, and mitigate tolerances, thereby reducing costs.

[0039] (2) The rigidity of the side wall is lower than the rigidity of the fixing portions 20a to 20e in the inverter case 17. This makes it possible to reduce the weight of the inverter case 17 and strengthen the rigidity of the fixing portions 20a to 20e.

[0040] (3) Capacitor 16 is arranged so as to connect a pair of opposing side walls among the plurality of side walls. This ensures the strength of inverter case 17.

[0041] (4) A pair of fixing portions 20a to 20e and the corners of capacitor 16 form a truss shape when viewed from cover 11. This ensures the strength of the components in capacitor 16 and expands the range of influence of the beam.

[0042] (5) The plurality of fixing portions 20a to 20e include a combination of fixing portions provided at different positions in the thickness direction of the capacitor 16. This ensures the strength of the components of the capacitor 16 and expands the range of influence of the beam.

[0043] (6) The plurality of fixing portions 20a to 20e include a combination of fixing portions arranged at the same position in the thickness direction of the capacitor 16. This ensures the strength of the capacitor 16 component, expands the range of influence of the beam, and ensures manufacturability.

[0044] The present invention is not limited to the above-described embodiments, and various modifications and other configurations can be combined without departing from the spirit thereof. The present invention is not limited to a configuration having all the configurations described in the above-described embodiments, and also includes a configuration in which a portion of the configuration is deleted. Explanation of symbols

[0045] 1. Inverter, 1a. First space portion, 1b. Second space portion, 1c. Opening portion, 2. Motor housing, 3. Housing connection portion, 11. Top cover, 12. LV connector, 13. Ground substrate, 14. Power module, 15. Bus bar, 16. Capacitor, 16a to 16c. Corner portion, 17. Inverter housing, 17a. Housing fixing portion, 17b. Capacitor fixing portion, 18. DC connector, 20. Fixing member, 20a to 20e. Fixing portion.

Claims

1. A power conversion device, which is connected and fixed to a motor housing that accommodates a motor, characterized in that: The power conversion device comprises: a housing having a plurality of side walls and an opening on the motor side; a cover covering a top surface of the housing; and a plurality of internal components housed within the housing, The plurality of internal components include capacitors, The housing includes a connection portion connected to the motor housing and a plurality of fixing portions for fixing the capacitor inside the housing. In the housing, a first space is provided between the capacitor and the cover, and a second space is provided between the capacitor and the motor. The plurality of internal components are arranged so as to connect a pair of opposing side walls among the plurality of side walls.

2. The power conversion device according to claim 1, wherein: The rigidity of the side wall is lower than the rigidity of the fixing portion.

3. The power conversion device according to claim 1, wherein: The capacitor is arranged so as to connect the pair of opposing side walls among the plurality of side walls.

4. The power conversion device according to claim 1, wherein: A pair of the plurality of fixing portions and a corner portion of the capacitor form a truss shape when viewed from the cover side.

5. The power conversion device according to claim 1, wherein: The plurality of fixing portions include a combination of the fixing portions provided at positions different from each other in the thickness direction of the capacitor.

6. The power conversion device according to claim 1, wherein: The plurality of fixing portions include a combination of the fixing portions arranged at the same position in the thickness direction of the capacitor.

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